Let's Be Bad
by the.eye.does.not.SEE
Summary: All it takes is one night to shatter that good-girl image he had of her. From the halls of Seattle Grace to the Archfield and everywhere in between: "Let's be bad." Mark/Lexie, early season 5. Rated M.


Title: Let's Be Bad

Inspiration: You can thank the latest episode of _Smash _for this one. The second I heard _Let's Be Bad, _I instantly fell in love it. This story surfaced after I spent an entire day listening to the song non-stop.

PS: If you guys don't watch the show already, you should. The music is phenomenal, as is the dancing, acting, and storylines. Plus, there's an enormous amount of hot British guys. (Okay, there's only two, but for American television, that's a jackpot!) Bottom line, you can't go wrong with this show, no matter what you're looking for.

Rating: I think your mind went there when you read the title, but if you're a saint and it didn't, this fic will be rated M for some sexiness and a bit of swearing.

Background: Set in the fifth season, early Mark/Lexie. All of this takes place over the course of one day, the day after he approached her at Joe's and she recited the periodic table for him.

Summary: All it takes is one night to shatter that good-girl image he had of her. Mark can't hold himself back anymore, and Lexie feels herself giving in. From Seattle Grace to the Archfield and everywhere in between: "Let's be bad." Early season 5.

_._

**_If you say something is taboo,_**

**_Well, that's the thing I wanna do!_**

**_Do it to it, black and blue_**

**_Let's be bad_**

_._

"I thought I made this clear," Derek Shepherd calls, striding across the short linoleum hallway. He lowers his voice when he nears his best friend, and if Mark hadn't spent the last thirty-plus years around the man, he might even feel a little threatened by the way he growls out his next sentence. "I said, _stay away_ from Little Grey."

But he doesn't feel threatened. Actually, he's quite amused. Even the thought of the perfect Derek Shepherd threatening someone makes him laugh at the far-fetched possibilities.

"I wasn't kidding," the neurosurgeon pressing, noticing the self-assured smirk on his childhood friend's face. "This is serious. She is not another woman you can screw before moving onto the next."

"She's barely a woman at all," Mark laughs, exaggerating his amusement just to rile up his best friend. His smile widens when those honest blue eyes narrow, glaring at him.

"Exactly my point," Derek replies. "She's a girl. Leave her alone."

"And what makes you think I've been forcing my company on her?" Mark asks, forcing himself to sound bored while his mind runs through the late after-work hours they spent together at Joe's last night. His lip curls reflexively. Damn the periodic table. Why was it that the smart girls were the ones that always turned him on and then held his attention? Why couldn't she just be stupid and pretty instead of smart and pretty? And why did she have to smile so much? And laugh? Her damn laugh—

"Mark! Hello, are you even listening to me?"

The plastic surgeon almost jumps, his eyes snapping back to focus on his best friend. "Right. Stay away from Grey. Got it."

"I don't want to see you with her."

"Good; I don't want to be seen with her, either."

Derek stares at his childhood friend hard for a minute before mutter, "I'm trusting that you can handle yourself here," he says, eyeing the other man. "Am I wrong in thinking that you've matured?"

Mark smirks at him. "Would I tell you any answer but no?"

Derek closes his eyes, and Mark watches as he squeezes them shut for a long moment. When he finally opens them, he stares at the other surgeon for a long while.

"Just say away from her," are his parting words.

Not thirty seconds after the neurosurgeon departs, Mark hears someone clear their throat tentatively behind him. He already knows who it will be before he turns around, but he feels his mouth turn up in a slow smile at the sight of her. She's holding out a clipboard towards him.

"Dr. Bailey wanted your sign-off on this procedure," she tells him, passing over the medical brief. Mark scans the page quickly, picking out the important details. He reaches in his breast pocket for a pen. "It's for her patient with the—"

He raises his head, his eyes meeting hers. "I can read, you know, Grey. I don't need you to spell everything out for me."

"Right," she replies, looking down and taking a half-step back. "It's habit, sorry. I've been presenting this patient everyday since he was admitted."

Mark scribbles his signature at the bottom on the clipboard.

Lexie thanks him, taking the clipboard back before turning and heading down the hallway. She freezes, confused, when he calls her name. She turns around, surprised to find that the man who called her name is standing only a foot away. "Yes?" She asks, feeling her pulse pick up at his proximity and remembering their conversation at Joe's just last night.

He stares at her for a long, silent minute, and Lexie begins to feel herself fidget under his unwavering and intense gaze. Finally, she asks, "What?" She hates herself for the fact that her voice squeaks like a guilty child's. She clears her throat, trying to normalize her tone. "What is it?"

He stays silent, crossing his arms as he stares down at her. She tries not to stare at the muscles in his arms. _God, why can't he just be ugly and fat?_

"I was wondering what you impression of me is," he says finally.

Lexie swallows, finding the motion difficult. She hopes her face isn't heating up as much as she thinks it is. "My impression of you?" She wonders. _You're impossibly sexy._

"Yes, what do you think of me? Personally," he adds after a moment, not wanting to press her into a polite, professional answer.

"I…" Her eyes flicker across his face, not able to find the answer he wants written there. "I don't really know you personally," she finally settles on.

She watches, confused, as his gaze tightens on her. A second later, he turns away.

"I—I mean, you seemed fine last night," she calls after him before she can help herself. She watches him freeze mid-step, and is suddenly aware of the surrounding nurses staring at her and the public nature of their current situation. "Um, in surgery," she adds quickly, trying to cover her misstep. "You… Your surgery went well last night, right? I heard about it…" She trails off, sighing in relief and closing her eyes momentarily when her coworkers turn away, disinterested already at an intern's nonsensical babbling. Lexie almost jumps when she opens her eyes, finding him before her again.

"Last night?" He presses.

"At Joe's," she replies, keeping her voice low to avoid eavesdroppers. "You seemed perfectly fine to me."

He nods, processing this.

Lexie stares at him for a moment before stepping back. "Okay, then," she says, seeing this matter closed.

"Would you like to see?" He asks.

Lexie stares at him, confused. "Would I like to see what?"

"Who I really am."

She can't stop herself from smiling. "Is 'Mark Sloan' a fake name? Are you a criminal?"

He finds himself smiling back. "No, that's my real name. And I'm not a criminal…"

"But?"

He smirks at her. "Come to Joe's after your shift, and maybe you'll find out."

She stares at him for a quiet second before replying in a surprisingly serious whisper, "Maybe I will."

He finds her eyes just before she turns away, and he's struck by the maturity in them. They're dark, focused… And they were sizing him up like she knew exactly what was on his mind.

_Maybe I'm not the only bad one,_ Mark thinks to himself, watching her walk away. From the sinful images the soft sway of her hips puts in his head just seconds later as she departs, he's convinced once again that he's the worst. She's nowhere near him in the running.

He wonders, curious, if it will stop her anyway.

_._

**_Don't care if you've tied the knot_**

**_Most folks want what they ain't got_**

**_Melt the ice, make it hot_**

**_Let's be bad_**

_._

"So," Lexie begins, setting her drink on the table and hopping on the nearest barstool. "What's the 'but'?"

Mark Sloan glances over, feeling his lips curve in a smile at her appearance. "What do you think it is?"

She shakes her index finger at him. "No, no, no. We're not playing this game. You said I'd find out if I came to Joe's." She holds up her drink. "Well, I'm at Joe's."

"I said _maybe _you'd find out," Mark corrects with a smirk, holding up his own drink and clinking it against hers before taking a sip. "There was no definitive."

Lexie glares at him while she takes an annoyed swallow of her tequila. "My impression of you?" She asks when she sets her drink back down. He stares at her, more curious than he thought he'd be. He's almost leaning forward, practically desperate to know what she thinks—

"You suck," she finishes flatly.

He can't help but laugh, both at her answer and at his anticipation. His sounds of amusement are quickly lost in the bar's large crowd, but she hears them nonetheless and he watches as a smile flicks up her lips.

"I suppose I do," he replies after a moment.

"There's no 'suppose' about it," she replies, eyeing him with a small smirk.

He grins, leaning towards her and finding himself wanting to see more of this side of her. He saw a flash of it before—but this is so direct, so different. So personal.

"Tell me about you first," he finds himself saying. "And then maybe we'll talk about me."

She stares at him, skeptical. "You know me." She states it as if it's already a fact, and he wonders if, after tonight, it will be. "You know how I ramble. Do you really want to listen to all that for an hour?"

"Who says we're going to be here for just an hour?"

Lexie looks away, biting back a smile. "Fine," she replies when she turns her head back, feigning indifference. "What do you want to know?"

He shrugs, not caring where she begins as long as she begins, while he takes a sip of his scotch. But then he remembers how they spent the previous night in each other's company—

"When did you realize you had a photographic memory?"

Lexie's lips curve in a smile, and she shakes her head at the memory. "I was nine," she replies.

"And?" He prompts after a moment.

She meets his eyes with a grin. "If I tell you about my memory, you've gotta tell me something about yourself in return."

"Alternating twenty questions, is it?" He shifts in his seat with a smile. "Fine. I'll bite. What happened when you were nine?"

"Why did you invite me here tonight?"

"I asked you first," he replies triumphantly.

She rolls her eyes. "Fine. But it's a long story," she warns him.

He shrugs, lifting his glass to take a sip. "I've got time."

. . .

"I'm curious," Lexie says hours later, long after they've lost track of time, "why haven't you asked me any personal questions?"

"I've asked you plenty of personal questions," Mark replies, picking up a lonely fry from what used to be an enormous pile between them. He chews it slowly, just for something to do, while she stares at him.

"Why haven't you asked if I'm involved with anyone?" She wonders, her eyes never leaving his face.

Mark shrugs. "I don't care if you are or not."

Lexie lifts her chin, letting it fall in a slow, skeptical nod.

"What?" He replies. "I don't."

She smirks, amused. "You're awfully sure of yourself, aren't you?"

"What can I say?" He jokes. "I'm a confident guy."

Lexie's disapproving reply is lost to the noise of six chairs scraping across the bar's floor. Mark and Lexie glance to the far side of the bar, surprised to a crowd of people heading to the exit. Their eyes sweep over the rest of the bar, even more surprised to find it to be completely empty. Even Joe has disappeared in a back room; they're the only two left in the entire establishment.

"I guess it's… gotten late," Mark notes, suddenly feeling incredibly awkward breaking the vast silence of the room. "We should probably go too…"

Lexie nods, slowly turning back to him. She watches in silence as he pulls out his wallet, paying for both their drinks and their scattered meals without a word.

She wants to tell him that she can pay for her share herself, but there's only one thing she can think of to say. She speaks before he can get to his feet, her words running together in her haste to keep him here, locked in this strange bubble of honest connection, with her.

"Why haven't you answered my original question?"

"Your original question?" Mark prompts, reclining back in his seat for a second to look at her.

"Yeah," Lexie replies, staring at him. "You never told me—why did you invite me here tonight?"

"Because I wanted to know what you thought of me," Mark replies automatically. His quiet voice sounds unrealistically loud in the empty bar.

She stares at him, and her dark eyes are surprisingly piercing. He gets the feeling she can see into his mind with just a quick flick of her eyes. "But the real reason?" She presses.

"That is the real reason."

She shakes her head, a small smile curving up her lips. "No… It's not." She leans forward, reaching across the bar. She takes the scotch out of his hand without looking, throwing back the last couple gulps in one fluid movement. He stares at her while she does so, bewildered and perplexed at her actions. She sets down the glass after it's empty, reaching for his hand and taking it in hers. She lifts it up, pressing it against the center of her chest before dragging it down the middle of her body. She releases his hand, and it remains where she left it—resting on her thigh, a hot taste of the rest of his body.

When she meets his eyes again, she feels a shot of desire shoot through her body at the look in his. His sky-blue irises have darkened like a coming storm on the horizon. She can't help but lean closer, and when their breaths begin to intermingle, she can feel his hand squeeze her leg of its own accord.

"What's the real reason?" She whispers, feeling somehow simultaneously spurring into action and frozen in place by the half-hidden lust in his eyes.

"I think you know the real reason," he replies huskily. Lexie feels her stomach clench at the sound of his voice, and while she's momentarily distracted, Mark takes the opportunity to close the distance between them and cover her mouth with his. He feels her jump beneath him in surprise, and he half-grins at her reaction, of her delicious mixture of innocent and bold.

A second later, he's the one surprised—she's slipped off her barstool, destroyed the space between them, and pressed herself against him to deepen the kiss. She secretly relishes in the groan she can feel travel from his lips to hers, and she quickly insinuates herself into his anatomy as he spreads his legs to make room for her. She steps between them, grabbing his free hand that had fallen from her thigh. She presses it against her lower back, letting his fingers just brush the curve of her ass.

When they break for air the next second, Mark and Lexie both automatically glance around for on-lookers, having already forgotten that there are none.

She turns back from their frenzied search with a grin. "Do you want to get out of here?" She wonders aloud.

_._

**_Here's my whistle, make it wetter!_**

**_Let me wear that scarlet letter!_**

**_When I'm bad, I'm even better_**

**_Let's be bad_**

**_._**

"Archfield," Mark growls in her ear. "Now."

"Now?" Lexie pouts, backing her body against his. She bites her lip in near-sinful excitement, rubbing ass against his groin. She grins over her shoulder when she can feel his erection, a hard and welcome contrast to her smooth bottom. "Why?" She calls about the music, blinking up at him through the flashing lights. "I like it here."

"You aren't the one with a painful hard-on," Mark mutters in her ear, his voice as strained as his body.

"Hm," Lexie smirks, sweeping an arm behind her to run it through his hair and pull his lips close. She swirls her hips against him, relishing in his deep groan that emanates through the kiss. Her body shudders at the sound, instinctively moving closer. "Are you implying that I'm arousing you, Dr. Sloan?"

"Grey, you have no idea," he grunts.

She spins around a moment later, pressing her front flush against his, and ignoring all the other dancing and jumping bodies around them, covers his mouth with hers. She moans loudly when his hands reach around her body, squeezing her ass and pressing her more firmly against his erection. His hands rise up her lower body a moment later, moving to cup her lower back and tug her close as his tongue enters her mouth. Lexie welcomes it willingly, and doing and a little exploring of her own, slips her hands down his body. In the darkness of the dance floor, she finds his arousal, squeezing it through the smooth material of his pants. He curses, low and husky, breaking their kiss as he searches for air.

"I'm uncomfortable in my clothes, too," she pants in a whisper, taking his hand and pressing it against her flat lower abdomen. "I wish you could feel how hot I am for you."

"This is why I suggested we go to the hotel," Mark reminds her, slipping his hand from hers and trailing it down her hip. He slips it under the hem of her skirt, and quicker than she would have thought possible, he's cupping her damp heat in his hand.

Uncontrollable shudders race through her body at his intimate touch, and she can do nothing but press herself against his hand and try to quiet her audible moans. She groans aloud—the impatient plea is lost to the pounding music surrounding them—and though Mark hears it, he refuses to give her anything more. Not here.

"Archfield," he says again. His voice is much more demanding this time and his eyes are darker and more intense. "_Now_."

Lexie nods, knowing it isn't a suggestion this time. It's an order.

She grabs his hand, twining their fingers together. "Let's go," she replies before pushes her way through the sweaty, crowded-in bodies, and pulling him along behind her.

_._

**_I can't see the use in waiting_**

**_Your lips are intoxicating_**

**_(Do my hips need some translating?)_**

**_Let's be bad!_**

_._

With the door slammed behind them, Mark wastes no time in smothering her lips with hers. He steps forward, towering over her and pressing her body back against the wood paneling of the door. He can feel her moan into his mouth, sense the pleasure-filled vibrations all over his body.

When their lips inevitably have to part, his move to her neck, sucking her skin. His lips cover her pulse point, and Lexie's head falls back against the door and a loud moan escapes her mouth at the feeling.

"You like that?" He whispers, moving his lips to the curve of her shoulder and pushing her shirt out of the way. Instead of being annoyed (as she figures she would be if it were anyone else), Lexie finds herself smiling at Mark's smugness, basking in his unending confidence. She shudders at the thought of all the things his confidence will get her.

And so she tries a little of her own.

"Fuck me," she whispers when his lips migrate back to her neck. She watches his head twitch in surprise at her boldness, his blue eyes flying to hers. "You heard me," she whispers with a growing smile. She leans forward, letting her lips brush his ear as she speaks, finally voicing the words her body had been shouting at him all night. "I want you to fuck me."

His eyes fall closed. "Little Grey," he manages through clenched teeth.

"I need you," she murmurs in his ear, not unlike the devil that's been whispering from its perch on his shoulder "I need you right now."

"You're Little Grey," he half-pants, as if just now realizing who he's spent the last eight hours with.

She nods. "Lexie," she corrects automatically.

Mark freezes, and suddenly his conversation with Derek from this morning comes rushing back to him_. Stay away. She's a girl. Little Grey. I trust you can handle yourself._

_ Am I wrong?_

"What is it?" Lexie asks, impatient to get back into it.

Mark shakes his head, attempting to clear his mind. "Nothing," he mutters, turning back to her. "It's just Derek."

She stares at him, waiting for an explanation of the involvement of her soon-to-be brother-in-law.

"He told me to stay away from you," Mark tells her finally.

"When?"

"Today," Mark admits. "This morning?"

Lexie chuckles, reaching up to run her hands over his neck. "Well, you sure lasted a good while," she notes sarcastically.

Mark ignores her mockery. "He made it seem like you were forbidden. Like we'd be cursed if we were ever together."

"I'm not cursed, don't worry. I won't put any hexes on you." Lexie grins a second later. "If I can help it, that is."

"You aren't the cursed one," Mark agrees after a moment, letting her teasing go unacknowledged. "I am." He stares at her, his voice suddenly serious. "He thinks I'm bad, he thinks I'll hurt you… And I am. I'm not a good person." He holds her gaze. "I probably will only end up hurting you," he informs her.

He watches in confusion as her mouth turns up in a smile after a moment. "So?" She wonders aloud. "If you end up hurting me, whatever. It'll be my fault for sticking around long enough to let you do so." Her smile widens to a saucy grin, and she steps closer, purposely knocking her hips against his. "And as for being bad," she whispers, placing her hands against his chest. She curls her fingers, digging her nails into his skin through his clothes. "I think I like bad."

He leans towards her, unable to hold back but finding that self-restraint doesn't seem to matter anymore. Not when she wants it too. "Do you, now?"

Lexie lets her eyes fall closed as a smile spreads over her face. "Oh, yeah," she whispers. Her lips brush against his with every word—almost kissing, but not quite. "And you know what?"

He stares at her, watching as her eyes blink open. Their dark brown irises stare up at him, hypnotizing in their seductive preached-about innocence.

"I wanna be bad too," she whispers. Her voice is soft like the admission is a secret confession, known only to him. "Can you help me be bad?"

He smiles a half-second later, realizing that his hunch was probably the truth. "Believe it or not," he murmurs, bending over her until the weight of his body presses her into the mattress, "I _do _think I can help you with that."

"Oh, please do," she grins, wrapping her legs tightly around his waist. "And hurry." She bucks her hips, pressing her sizzling sex against his. "Because I don't think I can wait much longer."

_._

**_Here's the key for my ignition_**

**_Hit the gas to my transmission_**

**_When you hear the things I'm wishing,_**

**_You won't offer opposition!_**

**_Let's prohibit prohibition!_**

**_Let's…_**

**_be…_**

**_BAD_****_!_**

_._

"You didn't need me to make you bad," Mark realizes a half-hour later with a lazy smirk. He looks over to catch her eye. "You're bad all by yourself."

Lexie grins, pressing her sweaty face into the pillow beneath her head. "Did it surprise you?" She asks, eyeing him.

"Well, it certainly seduced me," Mark replies.

Lexie laughs, turning on her side to stare at him. He does the same, and for a long while, they simply look at each other, not knowing what to say and not caring about the lengthy silence.

Finally, Lexie breaks the ice, more out of curiosity than necessity. "About Derek's one-and-done idea of us…" She trails off, tilting her head towards him. "What do you think?"

Mark exhales in quite amusement, and Lexie waits for an explanation. A moment later, a slow smile spreads over his face; Lexie feel her body heat up in anticipation of what he's planning. "I think I'm about ready for round two," he replies. "What about you?"

Lexie grins. "I've been ready all night."

Mark pauses at her knowing tone, tilting his head to study her. "You knew, didn't you?" He mutters.

"I knew what?" She asks distractedly, already rolling over to crouch above him. Her lips explore the smooth, muscled planes of his chest and abs while he speaks.

"You knew that I wanted you. You knew I was struggling not to give in…"

Lexie smiles, lifting her head to meet his gaze. "I've never seen a man try so hard _not _to sleep with me." She bends forward, pecking his lips quickly. "You were torturing yourself, doctor."

"I thought you…" He closes his eyes, remembering how Derek had referred to her and how much he'd believed his best friend. How much he'd underestimated her. "I thought you were an innocent little girl."

She grins. "And aren't the good girls always the best and baddest in bed?"

"In your case, most definitely." He pauses, wondering. "Is this what you're like with everyone?" He asks, curious if he's the only one she's acted this way around or if he's simply one more name on a list.

"Not really." She shrugs, reconsidering a moment later. "I mean, it's always been there—every girl has a bit of fire in them, after all. And sometimes you can't ignore the burn any longer, especially when it starts sparking."

"That explains tonight," he replies.

She grins, nodding. "Tonight, for example, I felt like taking a walk on the wild side."

He smirks. "And _I'm _the wild side?"

She shrugs. "Compared with the guys I've been with in the past…"

He laughs, leaning back against the bed as his hands move to cup her hips. "You still feel the fire?" He wonders after a second, squeezing her skin softly.

"Are you still breathing?" She shoots back with a smile. "Then _yes, _I do still feel the fire." She smirks a moment later, pressing herself against his returning arousal. "Do you want the fire, too? Do you wanna feel the heat?"

His eyes fall closed at the sensation of her body flush against his. "I already feel it," he murmurs, struggling to memorize the feeling. "And it feels…" He takes a breath, opening his eyes slowly to meet hers as he shifts beneath her. "It feels so good."

She grins, bending down to press her lips to his. She feels him angle his hips beneath her, and a moment later when he pushes himself inside her, she can't help but moan aloud. "I can feel your heat, too," she pants, gazing down at him, her eyes the perfect mixture of naughty and innocent. He watches as her lips curl up in a suggestive grin, and just to see that look of shock on her face, he flips them over and covers her body with his.

She laughs in surprise when he does so, and her eyes are bright and lively as he bends over her. He can see a touch of mischief in her eyes, keeping him on his toes as her hands grip his back, tugging him close, and as he begins to move within her again. Their laugher and jokes turn into moans and groans of pleasure, and when he releases within her for a second time, the name 'Little Grey' and all the innocence attached to that girl is forgotten. He shouts her name, and she shouts his, and they forget about all other obligations for a while, occupying themselves by pulling each other closer and being bad for as long as they can.

_._

**_So make it hot and that ain't bad!_**

_._

Author's Note: I know it was a bit OOC for Lexie, but that was the point. I don't know about you, but I like the idea of Mark bringing out Lexie's wild (or at least moreadventurous) side, especially in the early days. ;)

So what'd ya think? **Leave me a review!**


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